使用oms的4.2.1版本：
使用oms的数据迁移功能，在结构迁移中其中有四张表报错，报错如下，这个是什么原因造成的呢
(conn=14230) Table doesn’t exist Query: – [WARN] [CONVERT] The table charset: utf8 → utf8mb4
– [WARN] [CONVERT] The table collation: utf8_general_ci → utf8mb4_general_ci
create table nyt_notification (
id int(11) not null auto_increment,
message longtext not null,
url varchar(200),
is_viewed tinyint(1) not null,
is_emailed tinyint(1) not null,
created datetime(6) not null,
occurrences int(10) unsigned not null,
subscription_id int(11),
user_id int(11),
modified datetime(6) not null,
primary key (id),
constraint nyt_notification_subscription_id_5a132ae1_fk_nyt_subscription_id foreign key (subscription_id) references nyt_subscription (id) ON DELETE RESTRICT ON UPDATE RESTRICT,
constraint nyt_notification_user_id_acbb5c10_fk_account_user_id foreign key (user_id) references account_user (id) ON DELETE RESTRICT ON UPDATE RESTRICT
)
auto_increment=1
default charset=utf8mb4
default collate=utf8mb4_general_ci Parameters: []
